The present invention relates to novel dihydro-[1,2,3]triazolo-[4,5-d]pyrimidin-7-one, to processes for their preparation and to their use as medicaments, in particular as inhibitors of cGMP-metabolizing phosphodiesterases.
The synthesis of triazolopyrimidines has been described in J. Chem. Soc., C, 1971, 706. Fungicidal properties of dihydrotriazolopyrimidinones and their synthesis have been described in Liebigs Ann. 1984, 1848, by Nielsen et. al.
The synthesis of dihydrotriazolpyrimidinones by cyclization of an ester with an aminotriazolocarbonamide in the presence of a base has been described in J. Het. Chem. 1985, 22, 1607 by Biagi et al. and in Het. 1996, 42, 691 by Miyashita et al.; the analogous synthesis starting from amidines can be found in J. Chem. Soc., Perkin Trans. 1, 1979, 922.
Antiallergic properties of 1-unsubstituted dihydrotriazolopyrimidinones have been described in Eur. J. Med. Chem. 1975, 447, in J. Med. Chem. 1975, 1117 and in J. Am. Chem. Soc. 1978, 100, 6474. The synthesis of 5-amino-dihydrotriazolopyrimidinones has been described in J. Chem. Soc. 1961, 4433, and their antiviral activity has been reported in J. Med. Chem. 1987, 30, 1091 and J. Med. Chem. 1984, 27, 1416.
Anticytokine properties of 8-azaadenines are reported by Karanov et al. in Plant Growth Regul. 1993, 13, 7.
A synthesis method for azahypoxanthines and azaadenines is described by Biagi et al in J. Het. Chem. 1991, 28, 1351 and J. Het. Chem. 1989, 26, 39.
Anticonvulsive properties of 5-amino-dihydrotriazolopyrimidinones have been described in EP-288 431. Furthermore, the synthesis of 5-amino-dihydrotriazolopyrimidinones is described in J. Het. Chem. 1996, 33, 1605. Adenosine A1 receptor affinity of azaadenines and binding to adenosine deaminase has been reported in Farmaco 1996, 51, 395, Farmaco 1995, 50, 659 and Farmaco 1994, 49, 187.
Purine-nucleoside phosphorylase-inhibitory properties of azaguanines are described in J. Med. Chem. 1996, 39, 949.
Syntheses of dihydrotriazolopyrimidinones are furthermore found in Farmaco 1995, 50, 13, Farmaco 1994, 49, 183, Farmaco 1992, 47, 1457, Farmaco 1992, 47, 525 and in Chem. Ztg. 1990, 114, 246.
The synthesis of intermediates of the type II has been described in EP 0 229 011 and in J. Chem. Soc. 78, 1956, 5832.
Triazolopyrimidinones of the general formula (I) having the stated substitution pattern R1, A, D and L are novel.
The compounds according to the invention are potent inhibitors of either one or more of the phosphodiesterases which metabolize cyclic guanosine 3xe2x80x2,5xe2x80x2-monophophate (cGMP PDE""s). According to the nomenclature of Beavo and Reifsnyder (Trends in Pharmacol. Sci. 11, 150-155, 1990), these are the phosphodiesterase isoenzymes PDE-I, PDE-II and PDE-V.
An increase in the cGMP concentration can lead to beneficial antiaggregatory, antithrombotic, antiprolific, antivasospastic, vasodilative, natriuretic and diuretic effects. It can influence the short- or long-term modulation of vascular and cardiac inotropy, the pulse and cardiac conduction (J. C. Stoclet, T. Keravis, N. Komas and C. Kugnier, Exp. Opin. Invest. Drugs (1995), 4 (11), 1081-1100).
The present invention relates to dihydro-[1,2,3]triazolo-[4,5-d]pyrimidin-7-ones of the general formula (I) 
in which
R1 represents cycloalkyl having 3 to 8 carbon atoms, or represents a radical of the formula 
xe2x80x83in which
R2 represents straight-chain or branched alkyl having up to 10 carbon atoms which is optionally substituted by hydroxyl,
E represents a radical of the formula xe2x80x94CH2xe2x80x94T,
xe2x80x83in which
T represents a straight-chain or branched alkylene chain having up to 10 carbon atoms,
R3 represents hydrogen or aryl having 6 to 10 carbon atoms which is optionally substituted up to 3 times by identical or different substitutents from the group consisting of halogen, hydroxyl, nitro, trifluoromethyl and straight-chain or branched alkyl or alkoxy having in each case up to 6 carbon atoms,
A and D represent hydrogen,
or
A represents hydrogen
and
D represents hydroxyl,
or
A and D together represent a radical of the formula xe2x95x90O,
L represents a radical of the formula 
represents aryl having 6 to 10 carbon atoms or represents a 5- to 7-membered aromatic, optionally benzo-fused heterocycle having up to 3 heteroatoms from the group consisting of S, N and/or O, where the ring systems listed above under L are substituted up to 3 times by one or more identical or different of the following substituents: halogen, hydroxyl, nitro, trifluoromethyl, carboxyl, straight-chain or branched alkyl, alkoxy and alkoxycarbonyl having in each case up to 6 carbon atoms, a radical of the formula xe2x80x94(V)axe2x80x94NR4R5,
xe2x80x83in which
a represents a number 0 or 1,
V represents a radical of the formula xe2x80x94CO or xe2x80x94SO2,
R4 and R5 are identical or different and represent hydrogen or straight-chain or branched acyl or alkoxycarbonyl having in each case up to 6 carbon atoms, or
xe2x80x83represent straight-chain or branched alkyl having up to 6 carbon atoms which is optionally substituted by hydroxyl, amino or by straight-chain or branched alkyl- or dialkylamino having in each case up to 6 carbon atoms, or
R4 and R5 together with the nitrogen atom form a 5- or 6-membered saturated heterocycle which may optionally contain a further heteroatom from the group consisting of S and O or a radical of the formula xe2x80x94NR6 and which is optionally substituted by straight-chain or branched alkoxycarbonyl having up to 6 carbon atoms,
xe2x80x83in which
R6 represents hydrogen or straight-chain or branched alkyl having up to 4 carbon atoms,
and/or the ring systems listed under L are optionally substituted by aryl having 6 to 10 carbon atoms and a 5- to 7-membered aromatic, optionally benzo-fused heterocycle having up to 3 heteroatoms from the group consisting of S, N and O, where these ring systems for their part are optionally substituted up to 2 times by identical or different substituents from the group consisting of halogen, hydroxyl, nitro, carboxyl, trifluoromethyl and straight-chain or branched alkyl, alkoxy, or alkoxycarbonyl having in each case up to 5 carbon atoms, or by a group of the formula xe2x80x94(Vxe2x80x2)bxe2x80x94NR7R8,
xe2x80x83in which
b has the meaning of a given above and is identical to or different from this meaning,
R 7 and R8 have the meanings of R4 and R5 given above and are identical to or different from these meanings,
Vxe2x80x2 has the meaning of V given above and is identical to or different from this meaning,
and their tautomers and salts.
The substances according to the invention can also be present as salts. In the context of the invention, preference is given to physiologically acceptable salts.
Physiologically acceptable salts can be salts of the compounds according to the invention with inorganic or organic acids. Preference is given to s alts with inorganic acids, such as, for example, hydrochloric acid, hydrobromic acid, phosphoric acid or sulphuric acid, or salts with organic carboxylic or sulphonic acids, such as, for example, acetic acid, maleic acid, fumaric acid, malic acid, citric acid, tartaric acid, lactic acid, benzoic acid, or methanesulphonic acid, ethanesulphonic acid, phenylsulphonic acid, toluenesulphonic acid, or naphthalenedisulphonic acid.
Physiologically acceptable salts can also be metal or ammonium salts of the compounds according to the invention. Particular preference is given, for example, to sodium, potassium, magnesium or calcium salts, and also to ammonium salts which are derived from ammonia or organic amines, such as, for example, ethylamine, di- or triethylamine, di- or triethanolamine, dicyclohexylamine, dimethylaminoethanol, arginine, lysine, ethylenediamine or 2-phenylethylamine.
The compounds of the general formula (I) according to the invention can be present in various stereochemical forms which are either like image and mirror image (enantiomers) or which are not like image and mirror image (diastereomers). The invention relates both to the different stereoisomers and to the racemic forms and the diastereomer mixtures. The racemic forms, like the diastereomers, can be separated into the stereoisomerically uniform components in a known manner.
In the context of the invention, cycloalkyl having 3 to 8 carbon atoms represents cyclopropyl, cyclopentyl, cyclobutyl, cyclohexyl, cycloheptyl or cyclooctyl. The following may be mentioned as being preferred: cyclopropyl, cyclopentyl and cyclohexyl.
Aryl having 6 to 10 carbon atoms generally represents an aromatic radical having 6 to 10 carbon atoms. Preferred aryl radicals are phenyl and naphthyl.
In the context of the invention, alkyl having up to 6 carbon atoms represents a straight-chain or branched alkyl radical having 1 to 6 carbon atoms. Preference is given to a straight-chain or branched alkyl radical having 1 to 4 carbon atoms. Particular preference is given to a straight-chain or branched alkyl radical having 1 to 3 carbon atoms. The following may be mentioned by way of example: methyl, ethyl, n-propyl, isopropyl, tert-butyl, n-pentyl and n-hexyl.
In the context of the invention, alkoxy having up to 6 carbon atoms represents a straight-chain or branched alkoxy radical having 1 to 6 carbon atoms. Preference is given to a straight-chain or branched alkoxy radical having 1 to 4 carbon atoms. Particular preference is given to a straight-chain or branched alkoxy radical having 1 to 3 carbon atoms. The following may be mentioned by way of example: methoxy, ethoxy, n-propoxy, isopropoxy, tert-butoxy, n-pentoxy and n-hexoxy.
In the context of the invention, alkoxycarbonyl having up to 6 carbon atoms represents a straight-chain or branched alkoxycarbonyl radical having 1 to 6 carbon atoms.
Preference is given to a straight-chain or branched alkoxycarbonyl radical having 1 to 4 carbon atoms. Particular preference is given to a straight-chain or branched alkoxycarbonyl radical having 1 to 3 carbon atoms. The following may be mentioned by way of example: methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxycarbonyl and tert-butoxycarbonyl.
In the context of the invention, acyl having up to 6 carbon atoms represents a straight-chain or branched acyl radical having 1 to 6 carbon atoms. Preference is given to a straight-chain or branched acyl radical having 1 to 4 carbon atoms. Particular preference is given to a straight-chain or branched acyl radical having 1 to 3 carbon atoms. The following may be mentioned by way of example: acetoxy, ethylcarbonyl or n-propylcarbonyl.
In the context of the invention, heterocycle generally, depending on the substituent in question, represents an aromatic, optionally benzo-fused or unsaturated 5- to 7-membered, preferably 5- or 6-membered, heterocycle which may contain up to 3 heteroatoms from the group consisting of S, N and O, or represents a 5- or 6-membered saturated heterocycle which may optionally contain a further heteroatom from the group consisting of S and O. The following may be mentioned by way of example: pyridine, pyrimidyl, piperazinyl, thienyl, furyl, morpholinyl, pyrrolidinyl, piperazinyl or piperidyl. Preference is given to pyridine, thienyl, morpholinyl and piperidinyl.
In the context of the invention, halogen generally represents fluorine, chlorine, bromine and iodine. Preference is given to fluorine, chlorine and bromine. Particular preference is given to fluorine and chlorine.
Preference is given to compounds of the general formula (I),
in which
R1 represents cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl, or represents a radical of the formula 
xe2x80x83in which
R2 represents straight-chain or branched alkyl having up to 8 carbon atoms which is optionally substituted by hydroxyl,
and
E represents a radical of the formula xe2x80x94CH2xe2x80x94Txe2x80x94,
xe2x80x83in which
T represents a straight-chain or branched alkylene chain having up to 8 carbon atoms,
R3 represents hydrogen or phenyl which is optionally substituted up to 2 times by identical or different substituents from the group consisting of fluorine, chlorine, bromine, hydroxyl, nitro, trifluoromethyl and straight-chain or branched alkyl or alkoxy having in each case up to 5 carbon atoms,
A and D represent hydrogen,
or
A represents hydrogen
and
D represents hydroxyl,
or
A and D together represent a radical of the formula xe2x95x90O,
L represents a radical of the formula 
represents phenyl, naphthyl, pyridyl, thienyl, indolyl or furyl, which are optionally substituted up to 3 times by identical or different substituents selected from the group consisting of fluorine, chlorine, bromine, trifluoromethyl, hydroxyl, nitro, carboxyl, straight-chain or branched alkyl, alkoxy and alkoxycarbonyl having in each case up to 5 carbon atoms and/or by a radical of the formula xe2x80x94(V)aNR4R5,
xe2x80x83in which
a represents a number 0 or 1,
V represents a radical of the formula xe2x80x94CO or xe2x80x94SO2,
R4 and R5 are identical or different and represent hydrogen or straight-chain or branched acyl or alkoxycarbonyl having in each case up to 4 carbon atoms, or
represent straight-chain or branched alkyl having in each case up to 5 carbon atoms which is optionally substituted by hydroxyl, amino or by straight-chain or branced alkyl- or dialkylamino having in each case up to 5 carbon atoms,
or
R4 and R5 together with the nitrogen atom form a morpholinyl, piperidinyl or piperazinyl ring which is optionally substituted via a nitrogen atom by straight-chain or branched alkyl having up to 3 carbon atoms, which rings are optionally substituted by straight-chain or branched alkoxycarbonyl having up to 4 carbon atoms,
and/or the ring systems listed under L are optionally substituted by naphthyl, phenyl, pyridyl, indolyl, thienyl and furyl which are optionally substituted by fluorine, chlorine, bromine, hydroxyl, nitro, carboxyl, trifluoromethyl or by straight-chain or branched alkyl, alkoxy or alkoxycarbonyl having in each case up to 3 carbon atoms or by a group of the formula xe2x80x94(Vxe2x80x2)bNR7R8,
xe2x80x83in which
b has the meaning of a given above and is identical to or different from this meaning,
Vxe2x80x2 has the meaning of V given above and is identical to or different from this meaning,
R7 and R8 have the meanings of R4 and R5 given above,
and their tautomers and salts.
Particular preference is given to compounds of the general formula (I)
in which
R1 represents cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl, or represents a radical of the formula 
xe2x80x83in which
R2 represents straight-chain or branched alkyl having up to 7 carbon atoms which is optionally substituted by hydroxyl,
and
E represents a radical of the formula xe2x80x94CH2xe2x80x94Txe2x80x94,
xe2x80x83in which
T represents a straight-chain or branched alkylene chain having up to 7 carbon atoms,
R3 represents hydrogen or phenyl which is optionally substituted up to 2 times by identical or different substituents from the group consisting of fluorine, chlorine, bromine, hydroxyl, nitro, trifluoromethyl and straight-chain or branched alkyl or alkoxy having in each case up to 4 carbon atoms,
A and D represent hydrogen,
or
A represents hydrogen
and
D represents hydroxyl,
or
A and D together represent a radical of the formula xe2x95x90O,
L represents a radical of the formula 
represents phenyl or pyridyl which are optionally substituted up to 3 times by identical or different substituents selected from the group consisting of fluorine, chlorine, bromine, trifluoromethyl, hydroxyl, nitro, carboxyl, straight-chain or branched alkyl, alkoxy and alkoxycarbonyl having in each case up to 4 carbon atoms and/or by a radical of the formula xe2x80x94(V)aNR4R5,
xe2x80x83in which
a represents a number 0 or 1,
V represents a radical of the formula xe2x80x94CO or xe2x80x94SO2,
R4 and R5 are identical or different and represent hydrogen or straight-chain or branched acyl or alkoxycarbonyl having in each case up to 3 carbon atoms, or
represent straight-chain or branched alkyl having in each case up to 4 carbon atoms which is optionally substituted by hydroxyl, amino or by straight-chain or branched alkyl- or dialkylamino having in each case up to 3 carbon atoms,
or
R4 and R5 together with the nitrogen atom form a morpholinyl, piperidinyl or piperazinyl ring which is optionally substituted via a nitrogen atom by straight-chain or branched alkyl having up to 3 carbon atoms, which rings are optionally substituted by straight-chain or branched alkoxycarbonyl having up to 4 carbon atoms,
and/or the ring systems listed under L are optionally substituted by phenyl or pyridyl,
and their tautomers and salts.
Moreover, a process for preparing the compounds of the general formula (I) according to the invention has been found which is characterized in that
in the case where A, Dxe2x95x90H, compounds of the general formula (II), 
in which
R1 is as defined above,
are reacted with compounds of the general formula (III)
xe2x80x83Lxe2x80x94CH2xe2x80x94CO2R9xe2x80x83xe2x80x83(III)
xe2x80x83in which
L is as defined above
and
R9 represents C1-C4-alkyl,
in inert solvents, if appropriate in the presence of a base,
and the substituents listed under the substituents R1, R3 and L are, if appropriate, introduced or derivatized by subsequent reactions such as acylation, oxidation, substitution and/or reductions.
The process according to the invention can be illustrated in an exemplary manner by the equation below: 
Solvents which are suitable for the process are the customary organic solvents. These preferably include alcohols, such as methanol, ethanol, propanol, isopropanol, butanol or t-butanol, or ethers, such as tetrahydrofuran or dioxane, or dimethylformamide or dimethyl sulphoxide. Particular preference is given to using alcohols, such as methanol, ethanol, propanol, isopropanol and acetonitrile and dimethylformamide. It is also possible to use mixtures of the solvents mentioned.
Bases which are suitable for the process are the customary inorganic bases. These preferably include alkali metal hydroxides or alkaline earth metal hydroxides, such as, for example, sodium hydroxide, potassium hydroxide or barium hydroxide, or alkali metal carbonates, such as sodium carbonate or potassium carbonate or sodium bicarbonate, or alkali metal alkoxides, such as sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide or potassium tert-butoxide. Particular preference is given to sodium methoxide and sodium ethoxide.
When carrying out the process, the base is generally employed in an amount of from 2 to 6 mol, preferably from 3 to 5 mol, based on 1 mol of the corresponding amides.
The process is generally carried out at atmospheric pressure. However, it is also possible to carry out the process at elevated pressure or reduced pressure (for example in a range of from 0.5 to 5 bar).
The reaction with alkylsulphonyl chlorides is carried out, starting from the corresponding free hydroxyl compounds, in one of the abovementioned solvents and one of the bases, preferably using dichloromethane, triethylamine or pyridine, in a temperature range of from xe2x88x9220C to +20xc2x0 C., preferably 0xc2x0 C., and at atmospheric pressure.
The azide radical is generally introduced by reacting the corresponding alkylsulphonyloxy-substituted compounds with sodium azide in one of the solvents listed above, preferably dimethylformamide and dimethyl sulphonyl, in a temperature range of from 50xc2x0 C. to +120xc2x0 C., preferably 50xc2x0 C., and at atmospheric pressure.
The enantiomerically pure compounds are obtainable by customary methods, for example by chromatography of the racemic compounds of the general formula (I) on chiral phases, or by using chiral starting materials.
Some of the compounds of the general formula (II) are known and some are novel and can be prepared, for example, by reacting compounds of the general formula (IV)
xe2x80x83N3xe2x80x94R1xe2x80x83xe2x80x83(IV)
in which
R1 is as defined above
with compounds of the formula (V)
Nxe2x89xa1Cxe2x80x94CH2xe2x80x94COxe2x80x94NH2xe2x80x83xe2x80x83(V)
in inert solvents in the presence of a base.
Solvents which are suitable for the process are the customary organic solvents. These preferably include alcohols, such as methanol, ethanol, propanol, isopropanol, butanol or tert-butanol, or ethers, such as tetrahydrofuran or dioxane, or dimethylformamide or dimethyl sulphoxide. Particular preference is given to using alcohols, such as methanol, ethanol, propanol, isopropanol, and acetonitrile, dimethylformamide and dimethyl sulphoxide. It is also possible to use mixtures of the solvents mentioned.
Bases which are suitable for the process are the customary inorganic bases. These preferably include alkali metal hydroxides or alkaline earth metal hydroxides, such as, for example, sodium hydroxide, potassium hydroxide or barium hydroxide, or alkali metal carbonates, such as sodium carbonate or potassium carbonate or sodium bicarbonate, or alkali metal alkoxides, such as sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide or potassium tert-butoxide. Particular preference is given to sodium methoxide and sodium ethoxide.
The process is generally carried out in a temperature range of from 0xc2x0 C. to +180xc2x0 C., preferably of from +20xc2x0 C. to +150xc2x0 C.
The process is generally carried out at atmospheric pressure. However, it is also possible to carry out the process at elevated pressure or reduced pressure (for example in the range of from 0.5 to 5 bar).
The compounds of the general formulae (IV) and (V) are known per se or can be prepared by customary methods.
The compounds of the general formula (I) according to the invention have an unforeseeable useful pharmacological activity spectrum.
They inhibit either one or more of the c-GMP-metabolizing phosphodiesterases (PDE I, PDE II and PDE V). This leads to an increase of c-GMP. The differentiated expression of the phosphodiesterases in different cells, tissues and organs, as well as the differentiated subcellular localization of these enzymes, in combination with the selective inhibitors according to the invention make it possible to selectively address the various cGMP-regulated processes.
Moreover, the compounds according to the invention enhance the activity of substances such as, for example, EDRF (endothelium derived relaxing factor), ANP (atrial natriuretic peptide), of nitrovasodilators and all other substances which increase the cGMP concentration in a manner different from that of phosphodiesterase inhibitors.
They can therefore be employed in medicaments for treating cardiovascular disorders, such as, for example, for treating hypertension, neuronal hypertension, stable and unstable angina, peripheral and cardiovascular disorders, arrhythrnias, for treating thromboembolic disorders and ischaemias such as myocardial infarction, stroke, transistory and ischaemic attacks, angina pectoris, obstruction of peripheral circulation, prevention of restenoses after thrombolysis therapy, percutaneous transluminal angioplasty (PTA), percutaneous transluminal coronary angioplasties (PTCA) and bypass. Furthermore, they may also be of significance for cerebrovascular disorders. Owing to their relaxing action on smooth muscles, they are suitable for treating disorders of the urogenital system such as hypertrophy of the prostate, incontinence and, in particular, for treating erectile dysfunction and female sexual dysfunction.
Activity of the Phosphordiesterases (PDEs)
The c-GMP-stimulated PDE II, the c-GMP-inhibited PDE III and the cAMP-specific PDE IV were isolated either from porcine or bovine heart myocardium. The Ca2+-calmodulin-stimulated PDE I was isolated from porcine aorta, porcine brain or, preferably, from bovine aorta. The c-GMP-specific PDE V was obtained from porcine small intestine, porcine aorta, human platelets and, preferably, from bovine aorta. Purification was carried out by anion exchange chromatography over MonoQR Pharmacia, essentially following the method of M. Hoey and Miles D. Houslay, Biochemical Pharmacology, Vol. 40, 193-202 (1990) and C. Lugman et al. Biochemical Pharmacology Vol. 35 1743-1751 (1986).
The enzyme activity is determined using a test mixture of 100 xcexcl in 20 mM Tris/HCl buffer pH 7.5 containing 5 mM MgCl2, 0.1 mg/ml of bovine serum albumin and either 800 Bq 3HcAMP or 3HcGMP. The final concentration of the nucleotides in question is 10xe2x88x926 mol/l. The reaction is initiated by addition of the enzyme and the amount of enzyme is such that during the incubation time of 30 min, approximately 50% of the substrate is converted. To test the cGMP-stimulated PDE II, 3HcAMP is used as substrate and 10xe2x88x926 mol/l of non-labelled cGMP are added to the mixture. To test the Ca-calmodulin-dependent PDE I, 1 xcexcM of CaCl2 and 0.1 xcexcM of calmodulin are added to the reaction mixture. The reaction is quenched by addition of 100 xcexcL of acetonitrile, containing 1 mM cAMP and 1 mM AMP. 100 xcexcl of the reaction mixture are separated by HPLC and the cleavage products are determined quantitatively on-line using a continuous scintillation counter. The substance concentration measured is the concentration at which the reaction rate is reduced by 50%. Additionally, the xe2x80x9cphodiesterase [3H] cAMP-SPA enzyme assayxe2x80x9d and the xe2x80x9cphosphodiesterase [3H] cGMP-SPA enzyme assayxe2x80x9d from Amersham Life Science were used for testing. The test was carried out according to the test protocol of the manufacturer. To determine the activity of PDE2, the [3H] cAMP-SPA assay was used, and 10xe2x88x926 M cGMP were added to the reaction mixture to activate the enzyme. To measure PDE1, 10xe2x88x927 M calmodulin and 1 xcexcM CaCl2 were added to the reaction mixture. PDE5 was measured using the [3H] cGMP-SPA assay.
In principle, inhibition of one or more phosphodiesterases of this type results in an increase in the cGMP concentration. Thus, the compounds are of interest for all therapies in which an increase in the cGMP concentration is considered to be beneficial.
The cardiovascular effects were investigated using SH-rats and dogs. The substances were administered intravenously or orally.
The erection-stimulating action was investigated using rabbits which were awake [Naganuma H, Egashira T, Fuji J, Clinical and Experimental Pharmacology and Physiology 20, 177-183 (1993)]. The substances were administered intravenously, orally or parenterally.
The novel active compounds and their physiologically acceptable salts (for example hydrochlorides, maleates or lactates) can be converted in a known manner into the customary formulations, such as tablets, coated tablets, pills, granules, aerosols, syrups, emulsions, suspensions and solutions, using inert, non-toxic, pharmaceutically suitable excipients or solvents. In this case, the therapeutically active compound should in each case be present in a concentration from approximately 0.5 to 90% by weight of the total mixture, i.e. in amounts which are sufficient in order to achieve the dosage range indicated.
The formulations are prepared, for example, by extending the active compounds using solvents and/or excipients, if appropriate using emulsifiers and/or dispersants, it optionally being possible, for example, to use organic solvents as auxiliary solvents if the diluent used is water.
Administration is carried out in a customary manner, preferably orally, transdermally or parenterally, for example perlingually , buccally, intravenously, nasally, rectally or inhalatively.
In spite of this, it may be necessary to depart from the amounts mentioned below, namely depending on the body weight or the type of administration route, on the individual response towards the medicament, the type of its formulation and the time or interval at which administration takes place. Thus, in some cases it may be adequate to manage with less than the abovementioned minimum amounts, while in other cases the upper limit mentioned has to be exceeded. In the case of the administration of relatively large amounts, it may be advisable to divide these into several individual doses over the course of the day.
For human use, in the case of oral administration, it is good practice to administer doses of from 0.001 to 50 mg/kg, preferably 0.01 mg/kg-20 mg/kg. In the case of parenteral administration, it is good practice to use doses of from 0.001 mg/kg-0.5 mg/kg.
The compounds according to the invention are also suitable for use in veterinary medicine. For use in veterinary medicine, the compounds or their non-toxic salts can be administered in a suitable formulation in accordance with general veterinary practice. Depending on the kind of animal to be treated, the veterinary surgeon can determine the nature of use and the dosage.